Riddle extended his hitting streak to 19 games on Saturday, going 2-for-4 for Double-A Jacksonville. With a .382 average (29-for-76) and seven doubles during that stretch, the 24-year-old shortstop has raised his season average to .278 from .251.
Alvarez has been dominant since moving up to the Class A Midwest League, turning in back-to-back 10-strikeout performances in his first two starts for Great Lakes. The 20-year-old righty has fanned 20 of the 35 hitters he's faced as a member of the Loons while allowing three earned runs on nine hits and one walk in nine innings. All together, Alvarez has pitched to a 2.17 ERA with 46 strikeouts over 29 innings (seven starts) between the Arizona and Midwest Leagues.
Mahle, 21, had his worst start of the season on July 26, when he allowed seven earned runs on nine hits in 4 2/3 innings for Double-A Pensacola in a loss against Montgomery. The right-hander has been excellent otherwise, going 13-5 in 20 starts between Class A Advanced Daytona and Pensacola, with a 2.91 ERA, a 1.08 WHIP and a 108-30 strikeout-to-walk ratio in 117 2/3 innings.
Povse has yet to lose a game since being promoted to Double-A Mississippi, going 3-0 with a 2.59 ERA in his first four starts. Before moving up to the Southern League, the 6-foot-8 right-hander had posted a 3.71 ERA with 91 strikeouts and 17 walks over 87 1/3 innings (15 starts) for Class A advanced Carolina.
Sunday's Top 100 prospect probables
No. 4 Lucas Giolito (Nationals' No. 1), Syracuse at Buffalo (1:05 p.m. ET on MiLB.TV)
No. 21 Anderson Espinoza (Padres' No. 1) vs. Ryan Borucki (Blue Jays' No. 16), Fort Wayne vs. Lansing (1:05 p.m. ET)
No. 73 Jake Thompson (Phillies' No. 5), Lehigh Valley at Rochester (1:35 p.m. ET on MiLB.TV)
No. 84 Grant Holmes (Dodgers' No. 5), Rancho Cucamonga vs. High Desert (5:05 p.m. ET)
No. 95 Justus Sheffield (Indians' No. 5), Lynchburg at Winston-Salem (5:00 p.m. ET on MiLB.TV)
More top prospect probables
Jacob Faria (Rays' No. 6), Durham vs. Louisville (Triple-A) Robert Gsellman (Mets' No. 14), Las Vegas vs. El Paso (Triple-A) Chris Ellis (Braves' No. 16), Gwinnett at Toledo (Triple-A)
Adam Plutko (Indians' No. 16), Columbus at Charlotte (Triple-A)
Kyle McGowin (Angels' No. 18), Salt Lake at Sacramento (Triple-A)
Conner Greene (Blue Jays' No. 8), New Hampshire at Richmond (Double-A) Alec Mills (Royals' No. 9), Omaha vs. Iowa (Triple-A)
Jordan Guerrero (White Sox No. 9), Birmingham vs. Tennessee (Double-A)
Chance Adams (Yankees' No. 11) vs. Clay Holmes (Pirates' No. 15), Trenton vs. Altoona (Double-A)
Ariel Jurado (Rangers' No. 12), Frisco vs. San Antonio (Double-A) Taylor Guerrieri (Rays' No. 13), Montgomery vs. Jackson (Double-A)
Heath Fillmyer (A's No. 16), Midland at Corpus Christi (Double-A) Rob Kaminsky (Indians' No. 21), Akron vs. Bowie (Double-A)
Artie Lewicki (Tigers' No. 24), Erie vs. Reading (Double-A)
Trey Nielsen (Cardinals' No. 28), Springfield vs. Northwest Arkansas
Alex Young (D-backs' No. 4), Visalia at Stockton (Class A Advanced)
Sandy Alcantara (Cardinals' No. 9), Palm Beach vs. Tampa (Class A Advanced)
Jake Jewell (Angels' No. 13), Inland Empire vs. Lake Elsinore (Class A Advanced)
Francisco Rios (Blue Jays' No. 15), Dunedin vs. Jupiter (Class A Advanced) Yency Almonte (Rockies' No. 21), Modesto vs. San Jose (Class A Advanced)
Nick Neidert (Mariners' No. 4), Clinton at Kane County (Class A)
Mike Soroka (Braves' No. 6), Rome at Greenville (Class A)
Peter Lambert (Rockies' No. 12), Asheville at Columbia (Class A)
Scott Blewett (Royals' No. 13), Lexington at Charleston (Class A)
Gage Hinsz (Pirates' No. 23), West Virginia vs. Delmarva (Class A)
Jonathan Hernandez (Rangers' No. 27), Hickory vs. Hagerstown (Class A)
Kyle Funkhouser (Tigers' No. 6), Connecticut at Vermont (Class A Short Season)
Bryan Hudson (Cubs' No. 11), Eugene at Boise (Class A Short Season)
Matt Krook (Giants' No. 23), Salem-Keizer at Hillsboro (Class A Short Season)
Mike Rosenbaum is a reporter for MLB.com. Follow him on Twitter at @GoldenSombrero. This story was not subject to the approval of Major League Baseball or its clubs.